Overheating diagnosis needed on 1995 Lexus ES300

The temp gauge went up to the top two days ago. I let it sit and tried again. After a few minutes of driving, the temp gauge started to climb. I turned the heater to max, but it is not blowing very hot. I turned around to go home, and then the gauge went back down and the heat kicked in briefly. However, after 30 seconds or so, the gauge started climbing again and the air from the heater was not hot. Is this a thermostat issue?

by in Danville, CA on November 13, 2010
2 answers
ANSWER by on November 13, 2010
Here is a Diagnostic Check Sheet on the Diagnosis of an overheating engine that we at RepairPal put together to help people solve this issue ( or your shop ) http://repairpal.com/engine-overheating-diagnosis just follow the steps as well as you can, or have your shop do it. Look at item #4 i.e. coolant level, coolant leaks, do the cooling fans come on etc. It sounds like you are low on coolant for some reason, that may be why you aren't getting any heat, you need a full cooling system to transfer the heat into the the passenger compartment.
ANSWER by on November 24, 2010
If you remove the radiator cap what do you smell. If you smell exhaust gases then you may have blown head gaskets. The compressed gases have been forced into the cooling jackets and displaced the coolant. What does the expanision tank look like? The thermostat is under the alternator not a joy to get at but doable if you take your time. If you need some more help just call. Happy Holidays.